<html>
<head>
    <meta charset="UTF-8">
</head>
<body>
<form action="http:// xxx.com/register" id="registerForm" method="post"> 请输入用户名：<input type="text" name="userName"/>
    请输入密码：<input type="text" name="password"/> 请输入手机号码：<input type="text" name="phoneNumber"/>
    <button>提交</button>
</form>
<script>

    /***********************策略对象**************************/

    var strategies = {
        isNonEmpty: function (value, errorMsg) {
            if (value === '') {
                return errorMsg;
            }
        }, minLength: function (value, length, errorMsg) {
            if (value.length < length) {
                return errorMsg;
            }
        }, isMobile: function (value, errorMsg) {
            if (!/(^1[3|5|8][0-9]{9}$)/.test(value)) {
                return errorMsg;
            }
        }
    };

    /***********************Validator 类**************************/

    var Validator = function () {
        this.cache = [];
    };
    Validator.prototype.add = function (dom, rules) {
        var self = this;
        for (var i = 0, rule; rule = rules[i++];) {
            (function (rule) {
                var strategyAry = rule.strategy.split(':');
                var errorMsg = rule.errorMsg;

                self.cache.push(function () {
                    var strategy = strategyAry.shift();
                    strategyAry.unshift(dom.value);
                    strategyAry.push(errorMsg);
                    return strategies[strategy].apply(dom, strategyAry);
                });
            })(rule)
        }
    };

    Validator.prototype.start = function () {
        for (var i = 0, validatorFunc; validatorFunc = this.cache[i++];) {
            var errorMsg = validatorFunc();
            if (errorMsg) {
                return errorMsg;
            }
        }
    };
    /***********************客户调用代码**************************/

    var registerForm = document.getElementById('registerForm');
    var validataFunc = function () {
        var validator = new Validator();
        validator.add(registerForm.userName, [{strategy: 'isNonEmpty', errorMsg: '用户名不能为空'}, {
            strategy: 'minLength:6',
            errorMsg: '用户名长度不能小于 10 位'
        }])
        validator.add(registerForm.password, [{strategy: 'minLength:6', errorMsg: '密码长度不能小于 6 位'}]);
        validator.add(registerForm.phoneNumber, [{strategy: 'isMobile', errorMsg: '手机号码格式不正确'}]);
        var errorMsg = validator.start();
        return errorMsg;
    }

    registerForm.onsubmit = function () {
        var errorMsg = validataFunc();
        if (errorMsg) {
            alert(errorMsg);
            return false;
        }
    };

</script>
</body>
</html>
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